The exception is thrown by the method documentManager.getDocument(new PathRef("/pc-de-force/workspaces/import")), see code below.
User 'projetable_Eurpcf_Gest_01' is member of the group 'eurpcf_p_gestionnaires' so he has the permission 'Coordonnateur', see eurpcf-content-template-contrib.xml
The user has the 'Read' permission via the 'Coordonnateur' permission, see eurpcf-permissions-contrib.xml